KastorFlow vs NotebookLM Tools

Feature by feature

NotebookLM Tools' features as listed in nlmtools.com's llms.txt, its own summary of the extension, read November 6, 2026. Its home page didn't return readable text to us that day. — means they don't mention it, not that it can't be done. The KastorFlow column is checked against the extension itself. Spotted something out of date? Tell us and we'll fix it.

What Gemini Notebook does without either

NotebookLM Tools is strongest around Studio. Here is what Gemini Notebook itself did on November 6, 2026.

• Flashcards. Standard, from one 18-minute video, gave 52 cards in about a minute. The set's menu had only Delete: no download or export.
• Audio Overview. A Brief took about 4 minutes and came out 1 minute 39 seconds long. Its menu has Download, so you can save the file, but there's no podcast feed.
• Usage. On a personal account, chats and every Studio output draw on one allowance that refreshes every 5 hours, up to a weekly limit. A big batch can run out partway. Gemini Notebook's limits

What the differences mean in practice

After the reset, or on a trigger

NotebookLM Tools' timing setting runs what fits in your allowance now and has Gemini Notebook make the rest after the reset. That solves a batch running out partway. KastorFlow's automations solve a different problem, work that repeats. A rule starts on a tag, a new source, a schedule, or a finished audit, research build, YouTube import, Audio Overview or podcast episode, then imports, tags, audits, enriches or adds an episode to your podcast feed for you. Automations are on Pro. KastorFlow can also generate all Studio artifacts in one click (Pro).

An audit tells you which sources to trust

Gemini Notebook doesn't rate sources. KastorFlow's audit checks each source two ways. It scores how relevant and how authoritative the source is for the notebook's topic, and it flags broken, cut-off or cluttered text with a score from 0 to 10, where under 6 is worth cleaning. It also rates five kinds of source, authority, academic, community, recent and practitioner, as strong, good, thin or missing. That helps once a notebook has grown past what you remember adding.

Enrich then finds sources for each gap. Nothing goes in until you tick it, and never more than the notebook has room for. Free and Pro include 1 audit and 1 enrich a month; Pro+ has no monthly limit. How the audit works

Saving AI chats

KastorFlow puts a Save to NotebookLM button on ChatGPT, Claude, Gemini, Perplexity and Grok, so a long conversation becomes a source you can ask about later. Free includes 5 a day.

Flashcards and audio, out of the notebook

Both get flashcards to Anki, in different ways. NotebookLM Tools makes an Anki-ready CSV that you import yourself. KastorFlow sends a set straight into an Anki deck through AnkiConnect while Anki is open, or downloads a CSV. Free includes 1 send a month.

For audio, NotebookLM Tools plays Audio Overviews back to back and downloads them as MP3s. KastorFlow publishes them as episodes in your own podcast feed, which a podcast app can subscribe to, so they turn up on your phone without copying files. Pro includes 1,000 published minutes.

Keeping sources current

In our test, a web page or YouTube source's menu in Gemini Notebook had no refresh: to update one, you remove it and add it again. KastorFlow's Refresh sources brings in the new version of web pages that changed (Pro), and an automation can do it on a schedule. NotebookLM Tools' summary describes re-syncing stale Google Drive sources.

Try KastorFlow next to NotebookLM Tools

You don't have to switch to compare them. KastorFlow works on the same Gemini Notebook tabs and Google account, and reads the notebooks already there. Nothing needs moving.

1. Add KastorFlow to Chrome. No account is needed to start.
2. Audit a notebook you know well. In KastorFlow, open Research & improve → Audit and enrich, choose the notebook and run the audit. See whether the flagged sources are the ones you would have dropped.
3. Try a playlist as one source. Open a YouTube playlist, click the KastorFlow icon in Chrome's toolbar, choose Import playlist as one source and pick the notebook. It checks the notebook has room before it starts.

• KastorFlow keeps its own tags, folders and collections. It doesn't change Gemini Notebook's labels or Collections, or anything NotebookLM Tools has saved.
• Both can add buttons to the Gemini Notebook page. If something looks off, turn one off for a minute at chrome://extensions to see which it is.
• The library map and search across notebooks are free for 7 days, then need a free KastorFlow account.
• If you remove KastorFlow, your notebooks and the sources it added stay in Gemini Notebook.

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